The present invention relates to a sheet transfer machine useful for supplying sheet such as print sheet to an image forming portion of a printing section in an image forming machine of a printing machine.
A stencil printing machine as an image forming machine is generally provided with an ink supply mechanism at an inner portion thereof. The stencil printing machine includes a printing drum wound with perforated stencil sheet at an outer peripheral face thereof and driven to rotate and a printing section having pressing means for pressing print sheet to the printing drum. Further, the stencil printing machine is provided with a sheet transfer machine as a sheet supply machine and print sheet transferred therefrom is supplied to between the rotating printing drum and the pressing means.
FIG. 6 views a conventional sheet supply machine in a section orthogonal to a sheet supply direction. The sheet supply machine is provided with an upper guide plate 100 and a lower guide plate 101. The upper guide plate 100 and the lower guide plate 101 are arranged in parallel with each other at an interval therebetween. The upper guide plate 100 and the lower guide plate 101 are formed with hole portions at positions in correspondence with each other. The hole portions are provided with a pair of upper and lower guide roll 102 and timing roll 103. The two rolls 102 and 103 are constituted in a shape of comb teeth by being divided into pluralities of portions in axial directions.
Print sheet 1 constituting a sheet-like object supplied from the back face side of FIG. 6 is brought into an interval between the upper guide plate 100 and the lower guide plate 101. The print sheet 1 is sandwiched by the guide roll 102 and the timing roll 103 and is transferred to this side of FIG. 6. Although details are not illustrated, at a front side of a transfer direction, there is brought about a state in which the upper guide plate 100 is interrupted and only the lower guide plate 101 is extended to the front side. Further, the print sheet 1 comes out from between the upper and the lower guide plates 100 and 101 and guided along an upper face of the guide plate 101. At this occasion, as shown in FIG. 6, the print sheet 1 is transferred by being sandwiched by the pair of rolls 102 and 103 in the shape of comb teeth and therefore, there is brought about a state in which a swell (portion 1a of print sheet 1 formed in a wavy shape) is produced upwardly at a position of a gap between the two rolls 102 and 103 in the axial direction. That is, it seems that since the print sheet 1 is transferred by being sandwiched by the rolls in the shape of comb teeth, pressed states of the sheet differ at a location where the sheet is sandwiched and at other location. Accordingly, such a deformation (1a) in the wavy shape is caused.
When the print sheet 1 is sandwiched by the printing drum and the pressing means in such a state of causing the swell (deformation 1a), there arises a problem that the portion of the swell (deformation 1a) is crushed to constitute wrinkle.
It is an object of the invention to prevent a swell in a wavy shape from being caused in sheet in transferring the sheet and avoid the problem of causing wrinkle in later steps.
According to a first aspect of the invention, there is provided a sheet transfer machine having a guide plate, a first roll and a second roll and a press member. The second roll sandwiches sheet between the first roll and the second roll and transfers the sheet in a predetermined direction along the guide plate. The press member is arranged on a downstream side in the predetermined direction contiguously to the first and the second rolls for pressing sheet to the guide plate.
According to the first aspect of the sheet transfer machine, the sheet is sandwiched between the first roll and the second roll and is transferred in the predetermined direction along the guide plate. At this occasion, a swell is produced in the sheet. The transferred sheet is pressed on the guide plate by the press member. Thereby, the sheet produced with the swell can be brought into a flat state and transferred.
According to a second aspect of the invention, there is provided a sheet transfer machine provided at an image forming machine having an image forming drum driven to rotate and pressing means for forming an image on sheet by pressing the sheet to the image forming drum. The sheet transfer machine supplies the sheet to between the image forming drum and the pressing means. The sheet transfer machine is provided with a guide plate for guiding the sheet, a first roll, a second roll for sandwiching the sheet between the first roll and the second roll and transferring the sheet in a predetermined direction along the guide plate and a press member arranged on a downstream side of the predetermined direction contiguously to the first and the second rolls for pressing the sheet to the guide plate.
According to the second aspect of the sheet transfer machine, the sheet is sandwiched between the first roll and the second roll and guided to the guide plate. The sheet is transferred in the predetermined direction along the guide plate. At this occasion, a swell is produced in the sheet. The transferred sheet is pressed above the guide plate by the pressing members. The sheet produced with the swell is flattened and is supplied between the image forming drum and the pressing means. The sheet is pressed to the image forming drum driven to rotate by the pressing means. At this occasion, the swell is not produced in the sheet and therefore, even when the sheet is sandwiched between the pressing means and the image forming drum, wrinkle is not produced. Further, since image is formed on the sheet which is not produced with wrinkle and therefore, excellent image which is not warped can be formed.
According to a third aspect of the invention, there is provided a sheet transfer machine provided at an image forming machine including an image forming drum driven to rotate and pressing means for pressing sheet to the image forming drum and printing the sheet. The sheet transfer machine supplies the sheet between the image forming drum and the pressing means. The sheet supply machine is provided with guiding means, an upper roll, a lower roll and press members. The guiding means comprises an upper guide plate and a lower guide plate arranged at a predetermined interval therebetween. Hole portions are respectively formed at positions of the upper guide plate and the lower guide plate in correspondence with each other. The upper roll is arranged on an upper side of the upper guide plate proximately to the hole portions of the upper guide plate. The lower roll is arranged on a lower side of the lower guide plate proximately to the hole portions of the lower guide plate. The upper roll and the lower roll sandwich the sheet inserted between the upper guide plate and the lower guide plate therebetween. The upper roll and the lower roll transfer the sheet in a predetermined direction along the guiding means. The press members are arranged on a downstream side of the upper roll in the predetermined direction. The press members press the sheet transferred and coming out from between the upper guide plate and the lower guide plate to an upper face of the lower guide plate.
According to the third aspect of the sheet transfer machine, the sheet is inserted between the upper guide plate and the lower guide plate. The inserted sheet is sandwiched between the upper roll and the lower roll and is transferred in the predetermined direction along the guiding means. A swell (deformation) is produced in the sheet coming out from between the upper guide plate and the lower guide plate. The sheet produced with the swell is pressed by the press member at the upper face of the lower guide plate. Thereby, the sheet produced with the swell is flattened and is supplied between the image forming drum and the pressing means. The sheet is pressed to the image forming drum driven to rotate by the pressing means. At this occasion, the sheet is not produced with the swell and therefore, even when the sheet is sandwiched by the pressing means and the image forming drum, wrinkle is not produced. Further, the sheet which is not produced with the wrinkle is subjected to printing and therefore, excellent printing without warping can be carried out.
According to a fourth aspect of the invention, there is provided a sheet transfer machine wherein in the sheet transfer machine according to the third aspect, the press member is a hold roller which is brought into contact with the upper face of the lower guide plate movably in the up and down directions at a vicinity of an end edge of the upper guide late.
According to the fourth aspect of the sheet transfer machine, since the hold roller is used as the press member and therefore, the sheet produced with the swell coming out from between the upper guide plate and the lower guide plate is pressed by the hold roller above the lower guide plate and is brought into a flat state. And the hold roller is rotated by transferring the sheet. Thereby, the sheet can smoothly be transferred to direct to between the image forming drum and the pressing means.
According to a fifth aspect of the invention, there is provided a sheet transfer machine wherein in the sheet transfer machine according to the third aspect, the upper roll and the lower roll are divided into plural portions by interposing gap portions thereamong in the axial directions. The press members are arranged at positions contiguously to the gap portions in the predetermined direction.
According to the fifth aspect of the sheet transfer machine, the upper roll and the lower roll are divided into plural portions by interposing the gap portions thereamong in the axial directions in correspondence with a size of the sheet. Therefore, even when any size of the sheet is transferred, the sheet coming out from between the upper guide plate and the lower guide plate is produced with swells (deformations) at the gap portions between the upper roll and the lower roll. Portions of the sheet produced with the swells are pressed by the press members at the upper face of the lower guide plate. Thereby, the sheet produced with the swell is flattened and supplied to an interval between the image forming drum and the pressing means.
According to a sixth aspect of the invention, there is provided a sheet transfer machine which herein in the sheet transfer machine according to the third aspect, the upper roll and the lower roll are respectively single roll members. At least one of the press members is arranged at a position contiguous, in the predetermined direction, to central positions in the axial directions of the upper roll and the lower roll.
According to the sixth aspect of the sheet transfer machine, the upper roll and the lower roll are respectively single roll members and therefore, a number of parts can be reduced and in comparison with the case of using a plurality of the respective rolls, the maintenance can be facilitated. Further, since the two rolls are single roll members, there is frequently a case in which the sheet coming out from between the upper guide plate and the lower guide plate is produced with a swell (deformation) substantially at centers in the axial directions of the two rolls. Therefore, by arranging the pressing member at least to the central positions in the axial directions of the two rolls, the swell is crushed effectively and the sheet can be transferred in the flat state.